1. Field of the Invention
The present invention relates to a piezoelectric vibrator which is utilized for mobile information technology devices.
2. Background Information
In order to increase a degree of vacuum of a container which contains the piezoelectric vibrator, a method in which baking is done in vacuum before hermetic-sealing and a substance of a factor decreasing the degree of vacuum such as moisture adhering on surfaces of materials is removed has been conventionally used. In order to remove gas trapped inside the container, a method in which a small hole opened beforehand in the container is closed in vacuum by a technique generating little gas has been used.
In the method in which degassing is done by the baking before sealing, the gas generated during a sealing process is trapped in the container. Accordingly, oxygen, which is generated in case that the sealing is done by anode bonding, is trapped in the container to decrease the degree of vacuum. This results in an increase in equivalent series resistance R1. In case that the equivalent series resistance R1 is increased, such a problem is generated that battery life is decreased, when the piezoelectric vibrator is used for mobile devices. In the method in which the small hole opened beforehand in the container is closed in vacuum, another process different from the sealing process, in which the small hole is closed, is required, so that man-hour is increased.